1. Field of the Invention
The invention relates to cocoa components having enhanced levels of cocoa polyphenols, processes for producing the same, methods of using the same and compositions containing the same. More specifically, the invention provides a method of producing cocoa components having an enhanced content of cocoa polyphenols, in particular procyanidins. The cocoa components include partially and fully defatted cocoa solids, cocoa nibs and fractions derived therefrom, cocoa polyphenol extracts, cocoa butter, chocolate liquors, and mixtures thereof.
The invention also relates to versatile novel processes for extracting fat from cocoa beans and/or processing cocoa beans to yield a cocoa component having a conserved level of polyphenols, in particular procyanidins. The invention provides a significantly less complex process with respect to total cost of process equipment, maintenance, energy and labor, with the concomitant benefit of obtaining components having conserved concentrations of polyphenols relative to the starting materials.
2. Description of the Related Art
Documents are cited in this disclosure with a full citation for each. These documents relate to the state-of-the-art to which this invention pertains, and each document cited herein is hereby incorporated by reference.
Confections and other edible compositions containing cocoa components have a very distinct taste and mouthfeel that have been enjoyed by individuals for many years. The unique flavor and mouthfeel of chocolate, for example, is a result of the combinations of its numerous components as well as its process of manufacture. It is well known that the mouthfeel and aroma/flavor of a chocolate are factors which greatly influence the desirability of the final chocolate product. Accordingly, the primary focus of conventional processes using cocoa components is the development of the distinctive chocolate mouthfeel and flavor/aroma. Throughout the entire chocolate manufacturing process, from the selection of the cocoa beans as a commodity at the country of origin to the tempering and solidification of the final chocolate, the development of the appropriate mouthfeel and/or aroma/flavor of the final product dictates the selections made and the process parameters used.
Chocolate contains solid particles dispersed throughout a fat matrix. Factors that influence the mouthfeel of a chocolate include the particle size distribution of the solids, the properties of the fat matrix material and how the chocolate is made.
Cocoa butter is typically the predominant fat in the chocolates. Cocoa butter is solid at room temperature (21.degree.-24.degree. C.) and thus most chocolates are firm and solid at room temperature providing good "snap" at initial bite. Above room temperature, the fat phase melts progressively until it is completely melted at about 36.degree. C. This rapid melting in the mouth, at body temperature, provides the smooth, creamy mouthfeel which results in a strong flavor impact.
The flavor/aroma characteristics of the cocoa product are dependent on the combination of numerous solid and fat components as well as the process of manufacture. The flavor/aroma characteristics are dependent on (1) initial cocoa bean selection (i.e, level of fermentation, genotype, origin, etc.), (2) method of processing the beans (i.e., cleaning, roasting, shell removal, etc.) (3) processing of the cocoa components (i.e., milling) and (4) final processing to form the final product (i.e., selection of cocoa component and other ingredients, conching, etc.).
The several roles of selecting beans, fermenting them, cleaning them and processing them to obtain good flavor and other desirable characteristics is well known and is described below.
1. The Cocoa Bean
Cocoa beans are derived from cocoa trees which are found in warm, moist climates in areas about 20 degrees latitude north and south of the Equator. In general, the seeds of the Theobroma cacao (of the order Sterculiacae) are known chiefly in two varieties: Criollo and Forastero, with Forastero divided into several varieties. A third group, called Trinitario, is essentially a cross between Criollo and Forastero and is not found in the wild. Freshly harvested raw Criollo beans are pale brown in color while Forastero beans are a purple hue.
The cocoa bean is comprised of an inner nib portion covered by an outer shell. After conventional drying, the shell of the bean comprises about 12 to 15% of the weight of the bean, while the nib and residual moisture amounts to approximately 85 to 88%. Typical analytical data ranges for chemical components of cocoa nib are: fat content of 48 to 57%; theobromine content of 0.8 to 1.3%; caffeine content of 0.1 to 0.7%; total nitrogen content of 2.2 to 2.5%; ash content of 2.6 to 4.2%; and water content of 2.3 to 3.2% (see Pearson's Composition and Analysis of Foods, 9th Ed., 1991).
2. Fermentation of the Bean
Fermentation, an early step in the processing of cocoa beans, is important to the development of suitable flavors and/or flavor precursors. It was previously believed that fermentation and drying of the cocoa beans were "of vital importance as no subsequent processing of the bean will correct that practice at this stage" (Chocolate, Cocoa and Confectionery: Science and Technology, 3rd Ed., by Bernard W. Minifie, p. 13 (1989)). During the fermentation and drying processes, the unfermented wet beans taken from the pod lose about 65 percent of their weight, assuming the final optimum moisture content of 6 percent is attained (Minifie, p. 14). The level of fermentation in the dried cocoa bean is typically determined by the "cut test" (defined further below).
It is well known in the art that flavor in the final cocoa or chocolate is closely related to fermentation. For example, if the beans are cleaned and separated from the pulp and dried without any fermentation, the nib will not be the brown or purple-brown color of fermented dry cocoa beans but instead a slaty grey color (Industrial Chocolate Manufacture and Use, 2nd Ed., by S. T. Beckett, p. 13). Chocolate made from slaty, unfermented beans typically tastes very bitter and astringent without any apparent chocolate flavor (Beckett, p. 13).
Accordingly, fully fermented cocoa beans are more desirable than underfermented cocoa beans from a flavor/aroma standpoint and typically sell at a higher price. The fermented cocoa beans are usually used to produce chocolate liquors.
Underfermented beans are conventionally processed for their cocoa butter. The quality of the cocoa butter is not affected by underfermentation. The quality of the cocoa solids, however, is affected since they do not contain sufficient color, flavor/aroma and are therefore either discarded or sold for low-value uses. Although chocolate liquors and/or partially defatted cocoa solids are sometimes produced from a nonhomogeneous mass of beans containing a portion of underfermented beans, the resultant liquor or solids require subsequent treatment or processing. Since unfermented beans are not conventionally processed commercially, they are not typically available.
3. Bean Cleaning
Once the cocoa beans are selected, they are cleaned to remove extraneous matter and then processed. The initial step consists of cleaning the beans to remove extraneous non-cocoa materials. Conventional bean cleaning separates beans from extraneous non-cocoa materials by either size or density using a cleaning machine which is a gravity, vibratory or aspiration table (see Minifie, p. 35; Chocolate Production and Use, 3rd Ed., by L. Russell Cook, pp. 144-146; and Beckett, p. 55).
Current cocoa bean cleaning technology is typically limited in separation ability to a minimum density difference of 10-15%. This reduces the efficiency of achieving an accurate separation of bean and extraneous non-cocoa materials and therefore reduces the clean bean yield of the process. Additionally, conventional cleaning machines become easily clogged and require frequent cleaning. This also reduces the cleaning efficiency and the clean bean yield of the overall process.
Moreover, conventional cleaning machines have a tendency to fracture the beans during cleaning which reduces the percentage of whole beans available after cleaning. These broken bean pieces can later give rise to problems during roasting and winnowing. For instance, small bean pieces will burn readily at the elevated temperatures used during roasting and may result in burnt and ashy flavored liquors which are unacceptable from a flavor standpoint. Small bean pieces may also decrease the efficiency of the winnowing process because they can be lost during the aspiration of the shells and result in overall yield efficiency losses.
4. Bean Roasting
In most conventional processes, roasting of the whole bean or nib is an essential step in the manufacture of chocolate liquor or partially defatted cocoa solids. Whole bean roasting was previously believed to be critical for developing the natural flavor and aroma of the cocoa beans and reducing the moisture content of the bean to below about 2% by weight. Whole bean roasting also loosens the shell so that it can be readily removed during the winnowing process. The degree of cocoa roast is a time/temperature dependent relationship, where the time can vary from 5 to 120 minutes and the temperature of the whole bean can typically vary from 120.degree. C. to 150.degree. C. In the pre-roasting of whole beans, an initial heating step can be performed at just below 100.degree. C., followed by roasting of the nibs at elevated temperatures up to about 130.degree. C. (see Minifie, especially pp. 37 and 45-46; Cook, pp. 146-152; Beckett, pp. 55-64; and U.S. Pat. No. 5,252,349 to Carter, Jr.).
5. Winnowing-Shell Removal
The winnowing operation serves to separate the beans into the desired inner portion of the bean (nib) and the outer portion of the bean (shell). The principle of separation by a winnowing process depends on the difference in the apparent density of the nib and of the shell. Standard winnowing machines make use of the combined action of sieving and air aspiration. The shell is loosened during the conventional roasting and/or other heating steps. After loosening, the beans are typically broken between rollers to shatter the cocoa beans along natural fracture lines of the cocoa nib to facilitate shell removal during winnowing (see U.S. Pat. No. 2,417,078 to Jones; U.S. Pat. No. 5,252,349 to Carter, Jr.; Minifie, pp. 47-51; Cook, pp. 152-153; and Beckett, pp. 67-68).
Some cocoa bean processing techniques include a heat pre-treatment step to aid in the separation of the shell from the nib. This involves giving the beans a thermal shock by hot air, steam or infra-red heat (see U.S. Pat. No. 4,322,444 to Zuilichem et al.; British Patent No. 1,379,116 to Newton; Minifie, pp. 44-43; Cook, p. 155; and Beckett, pp. 60-62).
Infra-red heat pre-treatment uses infra-red heating to rapidly heat and expand the beans. This loosens the shells. The method consists of exposing the beans to infra-red radiation for a period of between one half and two minutes, during which time the beans are typically heated to a temperature of about 100 to 110.degree. C. The infra-red radiation used has a wavelength between 2 and 6 microns which corresponds to a frequency in the range of 0.7 to 1.2.times.10.sup.8 megacycles per second.
6. Formation of Chocolate Liquor and other Cocoa Components
The next step in conventional cocoa processing, after winnowing, involves nib grinding. Nib grinding is typically performed in two stages, an initial grinding stage to convert the solid nibs into a fluid paste and a final grinding stage to achieve the desired particle size. Both of these stages are equipment, maintenance, and energy intensive.
The cleaned roasted cocoa nibs typically vary in cocoa butter content from 50-58% by weight. During the grinding, the nib is ground, for instance by milling, into a fluid, dark brown "liquor". The fluidity is due to the breakdown of the cell walls and the release of the cocoa butter during the processing. Ground particles of partially defatted cocoa solids are suspended in the cocoa butter. This liquor is sometimes commercially sold as a product useful in the confectionery and baking industries where machinery for processing the cocoa beans is not available.
Other conventional cocoa processing includes separating cocoa butter from liquor. This is accomplished by using a batch hydraulic pot press ("hydraulic press") to separate the cocoa butter from the cocoa solids. The resultant cocoa butter is subsequently filtered to yield a clear, solid-free cocoa butter. Butter can also be produced by a continuous screw press to extract the butter from whole bean with shell or less frequently, from nibs (see U.S. Pat. No. 5,252,349 to Carter, Jr.; and Minifie, especially pp. 71-72).
The resulting cocoa cake from either hydraulic presses or screw presses may be milled into cocoa powder. Cocoa cake typically contains either 10-12% cocoa fat or 20-22% cocoa fat (see Minifie, pp. 72-76; Cook, pp. 169-172; and Beckett, pp. 78-82). Cocoa powder from cocoa cake obtained by hydraulic pressing is usually produced by milling the cocoa cake. If natural cocoa powder is desired, cocoa cake is fed directly to the cocoa cake mill. If alkalized cocoa powder is desired, the cake from an alkalizing process is fed to the mill. Hydraulic pressing produces a cocoa cake which is an agglomerate of previously milled cocoa particles. Cocoa cake mills for cocoa cake from hydraulic pressing are therefore designed to reduce the size of these agglomerates.
The natural cocoa cake or natural cocoa powder can be further processed by alkalizing to modify the color and flavor qualities of the cake (see U.S. Pat. No. 3,997,680 to Chalin; U.S. Pat. No. 5,009,917 to Wiant, et al.; Minifie, pp. 61-67; Cook, pp. 162-165; and Beckett, pp. 71-72). The alkalizing process can be used at any of several different stages of processing and includes the treatment of either the beans, liquor, nib, cake or powder with solutions or suspensions of alkali, usually, but not limited to, sodium or potassium carbonate. After alkalizing, the cocoa solids are dried and cooled. The dried cocoa solids are subsequently milled to produce alkalized cocoa powder, and thereafter cooled and packaged.
7. Polyphenols in Cocoa Beans and Their Utility
Cocoa beans contain polyphenols. These polyphenols have recently been extracted and screened for biological activity. It has been discovered that cocoa polyphenol extracts, particularly procyanidins, have significant biological utility. The extracts or compounds further separated therefrom have generally been prepared, on a laboratory scale, by reducing cocoa beans to a powder, defatting the powder, and extracting and purifying the active compound(s) from the defatted powder. The powder is generally prepared by freeze-drying the cocoa beans and pulp, depulping and deshelling the freeze-dried beans and grinding the deshelled beans or nibs. The extraction of active compound(s) has been accomplished by solvent extraction techniques, and the extracts have been purified by gel permeation chromatography, preparative High Performance Liquid Chromatography (HPLC) techniques, or by a combination of such methods (see U.S. Pat. No. 5,554,645 to Romancyzk et al.).
It has now been determined that the recovery of polyphenols appears to be inversely proportional to the degree of fermentation of the cocoa beans. Accordingly, the use of fermented beans as a feedstock material, which is important for good chocolate flavor, reduces the amount of polyphenols available in the cocoa component(s) derived from the beans.
It has also been determined that higher processing temperatures and/or longer processing times, e.g. in the roasting step, reduces the amount of polyphenols available in the cocoa components derived from the feedstock beans. Cocoa components have not, heretofore, been produced having substantial quantities of polyphenols. These problems in the art have not heretofore been recognized.